Factors affecting pregnancy rates following laparoscopic insemination of 28,447 Merino ewes under commercial conditions: A survey

Hill, , Thompson, JA and Perkins, NR (1998) Factors affecting pregnancy rates following laparoscopic insemination of 28,447 Merino ewes under commercial conditions: A survey. Theriogenology, 49 4: 697-709. doi:10.1016/S0093-691X(98)00019-3


Author Hill,
Thompson, JA
Perkins, NR
Title Factors affecting pregnancy rates following laparoscopic insemination of 28,447 Merino ewes under commercial conditions: A survey
Journal name Theriogenology   Check publisher's open access policy
ISSN 0093-691X
Publication date 1998-03-01
Year available 1998
Sub-type Article (original research)
DOI 10.1016/S0093-691X(98)00019-3
Open Access Status Not yet assessed
Volume 49
Issue 4
Start page 697
End page 709
Total pages 13
Place of publication NEW YORK
Publisher ELSEVIER SCIENCE INC
Language eng
Abstract The results of laparoscopic insemination of 28,447 Australian Merino-ewes with semen from 468 rams were used to study factors influencing pregnancy. The overall pregnancy rate was 71.7% (20,423/28,447). Pregnancy rates varied with type of progestagen implant, type- and dosage of PMSG, fresh or frozen semen, wool type and number of ewes inseminated per hour. The pregnancy rate (64.6%) obtained with Medroxy-progesterone acetate (MAP) sponges, was significantly (P < 0.01) lower than with Fluorogestone acetate 30 mg (FGA 30; 74.7%) sponges, Fluorogestone acetate 40 mg (FGA 40; 72.1%) sponges, and Controlled Internal Drug Release (CIDR-G;71.7%) implants. A PMSG dose of 200 IU resulted in significantly (P < 0.05) lower pregnancy rates (62.4%) compared with 250 IU (72.9%), 300 IU (79.1%) and greater than or equal to 375 IU (69.4%). The mean pregnancy rate for ewes administered Folligon PMSG was 71.9%, which was significantly higher (P < 0.001) than that of ewes treated with Pregnecol PMSG (65.8%). The use of Pregnecol PMSG and MAP sponges was associated, and thus their conditional effects could not be calculated. Ewes inseminated with fresh semen were significantly (P < 0.001) more likely to become pregnant (82.2%) than those inseminated with semen frozen in pellets (69.5%) or straws (71.6%). Ewes inseminated during the months of March, April or May (fall, 71.5%) were just as likely to become pregnant as those ewes inseminated in November, December, January or February (69.6%). Significantly (P < 0.05) fewer strong wool ewes become pregnant to laparoscopic AI, (67.6%) than fine (71.7%), fine medium (73%) or medium wool ewes. Significantly (P < 0.0001) more pregnancies (77.6%) were achieved when more than 55 ewes were inseminated per hour compared with fewer than 35 ewes per hour: (63.4%). (C) 1998 by Elsevier Science Inc.
Keyword Frozen-Thawed Semen
Artificial-Insemination
Breeding-Season
Ram Semen
In-Vitro
Sheep
Spermatozoa
Cryopreservation
Ovulation
Fertility
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: WoS Import
 
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Created: Sun, 07 Jan 2018, 05:19:06 EST